1. Field of the Invention
The invention relates generally to systems for delivering drinking water to animals and, more particularly, relates to a system and method for filling an animal watering bag in a sanitary environment and to a bag and a bag filling machine usable in such a system and method.
2. Discussion of the Related Art
A large and growing number of research facilities use lab animals in experimental research. These animals range in size from mice to non-human primates. The animals are typically housed in cages which may themselves be stored in rows on racks. Proper care of these animals is essential to these facilities. Infection, injury, or death to these animals is not only a loss of valuable animals but, perhaps worse, may also result in the loss of years of intensive research.
The cages for lab animals often form self-contained environments containing sources of food and water for the animals. In order to prevent the air in each cage from contaminating adjacent cages, the cages may be ventilated using a common air supply duct that supplies air to the cages, and a common exhaust manifold that draws air out of the cages, thereby leaving a slight positive pressure in the cages. The animals therefore remain isolated from one another to prevent the transfer of diseases. Systems of this type are disclosed, for example, in U.S. Pat. Nos. 5,954,013; 5,349,293; and 5,148,766, all of which are assigned to Lab Products, Inc. and all of which are incorporated by reference herein.
The cages on a particular rack may be supplied with drinking water either by individual water bottles or by a single water supply manifold connected to the individual cages by a plurality of animal watering valves, one of which is accessible by an animal in each cage. If water is supplied by a water manifold and animal watering valves, each cage may be coupled to both the air supply duct and the water supply manifold by a common docking assembly that extends into the rear wall of the cage. If, on the other hand, water is supplied by water bottles, each water bottle is self contained and simply rests on a wire bar lid disposed between a sealed plastic outer lid and the interior portion of the cage that houses the animal. In this case, a nipple or valve extends through the wire bar lid for access by the animal.
Water bottles are preferred over water manifolds by some facilities because, e.g., they require less piping than a facility having water manifolds. The major disadvantage of bottle-based systems is that substantial time and effort are required to clean, sterilize, fill, and reuse water bottles. The degree of effort required can be appreciated with reference to FIG. 1, which schematically illustrates a process for handling bottles in a bottle-based animal watering system. The process begins in an animal room 30 where empty or partially full contaminated bottles 32 are removed one at a time from the individual cages 34 on a rack 36 and placed in a basket 38 with other bottles 32. Each basket 38 typically contains 20 to 24 bottles. Once the basket 38 is full, a spring loaded top (not shown) is snapped in place to hold the bottles 32 in the basket 38, and the basket 38 is placed in a cart 40. When the cart 40, which typically can hold 6-8 baskets, is full, it is wheeled into a separate wash area 42, as represented by arrow 44. Then, for each basket 38, the stoppers (not shown) are removed from the bottles 32, and the basket 38 is inverted and placed on the feed conveyor 48 of a machine 46 known as a “tunnel washer.”. As the basket 38 is conveyed through the tunnel washer 46, the bottles 32 are cleaned through a cycle typically having pre-wash, detergent wash, acid rinse, cleanse rinse, and dry rinse phases. The basket 36 is then manually removed from the tunnel washer 44, turned back to its upright position, and stacked back on the cart 40.
After being filled with baskets of washed bottles, the cart 40 is wheeled to a bottle fill area 50 as represented by arrow 52, where the baskets 38 are fed one at a time through an automatic filling machine 54. The bottles 32 in the machine 54 are filled with plain water, treated water, or water containing nutrients or other additives. At the end of each fill cycle, clean stoppers are placed on the full bottles 32, and the full basket 38 is placed back on the cart 40.
Substantial manual effort is required for this and subsequent basket handling operations because the basket of full bottles typically weighs between 30 to 50 lbs. The degree of additional handling is application dependent. In less critical applications, a cart of full bottles can be transported directly from the fill area 50 back to the animal room 30. In other applications in which the animals are particularly fragile or in which contamination otherwise is of particular concern, the entire cart 40 and similarly filled carts are first placed in an autoclave 56 as represented by arrow 58 for sterilization, and only then is the cart 40 wheeled back into the animal room as represented by arrow 60.
In the animal room 30, bottles 32 are removed one at a time from the cart 40, sterilized manually using a spray bottle, and then placed in cages 34. This insertion takes place as part of a transfer process in which an animal is transferred from a soiled cage to a clean cage. The animal, food, and full water typically are placed in a clean cage in a type of change station usually known as a “change hood” 62, which constitutes a sanitary environment having a workbench which supports a clean cage during the transfer process. A typical change hood employs an appropriate filtering technique to isolate the air in the change hood from the air in the remainder of the room. For instance, the interior of the change hood 62 may draw air from the back of the change hood to an air intake on a front edge of the change hood's workbench. The air may be HEPA-filtered prior to being discharged back into the animal room 30. One such change hood is manufactured by The Baker Company of Sanford, Me.
Meanwhile, the soiled water bottle that is removed from the soiled cage during the change process is placed in a basket 38, perpetuating the cycle.
It should be apparent that the process described above is very time-consuming and labor intensive. It also can be very fatiguing given that a basket of full bottles can weigh from 30 to 50 lbs. It also is capital intensive, requiring the provision of a bottle washer, a fill station and, if desired, an autoclave. These expenses are all accrued in addition to those for the bottles and stoppers.
In addition, because the bottles 32 are filled outside of the animal room 30 in a non-sterile environment, the bottles may be contaminated, e.g., when filling the bottles, installing the stoppers, and/or transporting the filled bottles to the animal room.
In light of the foregoing, the need has arisen for an animal water supply system that requires less labor and less capital outlay than traditional bottle-based animal water supply systems.
Proposals have been made to eliminate at least some of the problems associated with handling glass or plastic water bottles by using plastic bags in at least some applications. For instance, U.S. Pat. Nos. 3,958,535, 4,022,159, and 4,130,088 to Salvia all disclose disposable plastic watering bags. However, rather than being configured to be filled on-site in an animal room, the bags are filled off-site and transported to the animal room in bulk. The transport of full bags to an animal room requires substantial manual effort and also substantially increases the risk of contamination.
More recently, published U.S. Patent Application Publication No. 2003/0226515 to Gabriel proposed a fluid delivery system in which disposable bags are formed and filled simultaneously using a so-called form fill and seal machine. The filled bags may then be sterilized after filling and/or handled in a change room or similar work station. However, the bags are not configured to be filled within a change hood or another sanitary environment in an animal room. Full bags must still be handled and transported at substantial manual effort and with substantial risk of contamination.
The need therefore has arisen to provide an animal water supply system that has a lower risk of contamination than a traditional bottle-based water supply system.
The need has also arisen to provide a disposable, sterile, easily handled water container that can be filled in a sanitary environment such as under a change hood.
The need additionally has arisen to provide a machine that could be mounted under a change hood or the like and that can automatically or manually fill a disposable animal watering container.